I. Field of the Invention
This invention relates to an electron beam exposure apparatus, and more particularly to an electron beam exposure apparatus in which an electron beam is passed through an aperture, and projected on a workpiece, having a reduced sectional shape corresponding to the shape of the aperture.
II. Description of the Prior Art
In manufacturing integrated circuit devices, etc., there are used electron beam exposure apparatus for exposing a resist film formed on a wafer to a predetermined pattern. In drawing a pattern with the minimum line width of 1 .mu.m or less by using these apparatus, it is promising that an electron beam emitted from an electron gun is passed through an aperture formed in a mask, condensed, and projected on a resist film as a condensed spot corresponding to the shape of the aperture. In doing this, however, there may be drawn a pattern with a size different from the desired size, due to a proximity effect resulting from scattering of electrons in the resist film during exposure. Such effect is specially remarkable with raster-scanning type exposure apparatus. In order to compensate for the proximity effect, the pattern has conventionally been drawn by using an electron beam having an increased charge density. In the prior art exposure apparatus to attain this, the mask portion around the aperture is formed in the shape of a sharp knife edge, and a wide opening surface of the aperture is directed to the workpiece side, thereby preventing the dispersion of the electron beam within the thickness of the mask. Although the exposure profile of the electron beam obtained by means of these exposure apparatus is substantially ideal, that is rectangular, it is still subject to a bad influence of the proximity effect.